RULES FOR THE USE OF THE PERIOD
516. The period is a mark of punctuation that denotes the completion of a sentence.
517. The period is used at the close of all assertive and imperative sentences. For example:
- There is talk of peace but preparation for war.
- Claim your own at any hazard.
518. The period is used after all initials and all abbreviations, as for example: E. V. Debs; T. P. O'Connor; Mr., Dr., Co., Mass., N. Y., C. O. D., F. O. B., U. S. A., etc.
519. The period is used to separate whole numbers and decimal numbers. For example: 3.1416 9.342.
A period is used for the decimal point between dollars and cents; as: $4.50, $2.25, $16.54, $35926.72.
It is also used to separate the various denominations of sterling money, as: £14. 15s. 6d.
520. The period is used after letters used as numerals or after figures used to number paragraphs, notes, remarks, questions or any list of particulars. For example:
The letters which are used to denote sub-heads in the enumeration of rules as a. b. c., etc., also the numerals and letters marking sections or sub-sections in chapters, as Chapter 8. Paragraph 1. Rule 1. Page 4. Volume 2. Paragraph 3. P. 16.
521. The period is also used after headings and titles, after dates and signatures to letters and other documents; also at the close of the address at the beginning of a letter, and of the name at the close of the letter; also after the last item in the direction of an envelope or package.